TODO: Implement real fee calculation in melt()

[shroominic]

TODO Location

sixty_nuts/wallet.py:634

Priority

🟡 Medium Priority - Important for preventing failed transactions

Current Code

fee_reserve = melt_quote.get("fee_reserve", 0)
total_needed = invoice_amount + fee_reserve
# TODO: check if we have enough balance in the target mint with real fee calculation

What needs to be done

• Calculate actual fees including both Lightning fees and mint input fees
• Verify sufficient balance exists after accounting for all fees
• Prevent failed melts due to insufficient balance

Implementation

1. Calculate mint input fees using calculate_total_input_fees()
2. Add Lightning fee reserve from melt quote
3. Verify balance covers amount + all fees
4. Trigger rebalancing if needed